Thorens TD-124 noise diagnosis

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One thing you can try is taping a few pennies to the headshell and rebalancing the arm. The change in mass should provide a quick answer as to whether or not you can tune whatever resonance this is to some point where it causes no mischief. The AVS-101 weighs about twice what the SME S2 headshell does, or are you using an S3 (solid/heavy) shell?
 
Hi
I think the Decca isn' t the issue because the V15 in an identical headshell makes exactly the same noise. So although it is rarely the case, the Decca isn't at fault this time! I have an SME weight somewhere that I can use to increase the mass. Will experiment. I am doubtful, but it would be great if additional headshell mass solved the problem. The SME shells are the light weight ones....

con
 
TD 124 probs

If you can spin the platter with a record on, and with the motor turned off, hear the noise, rebuild the platter bearing. If not, keep looking.

I am wondering if you might have a "stiction" issue. Here is how to find out.

Remove the belt, rub talcum powder on. Reinstall. Try it again. I had a problem that the talcum powder fixed, perhaps it will help you. BTW, if either pully is dirty with belt residue, clean them first, both must be perfectly clean. Don't overlook anything!

FYI I tried a rumble test on my 124, with a blank 45, and the needle down, volume turned way up, no rumble, just random noise caused by the needle rubbing against the vinyl. Have you also cleaned and oiled the intermediate pully? Could the idler be rubbing on the step pully, because it's mal-adjusted? EVERYTHING must be checked and perfect, don't overlook anything.

We will keep trying, wish you could hear mine to compare!

Gene
 
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If you can spin the platter with a record on, and with the motor turned off, hear the noise, rebuild the platter bearing. If not, keep looking.

I am wondering if you might have a "stiction" issue. Here is how to find out.

Remove the belt, rub talcum powder on. Reinstall. Try it again. I had a problem that the talcum powder fixed, perhaps it will help you. BTW, if either pully is dirty with belt residue, clean them first, both must be perfectly clean. Don't overlook anything!

FYI I tried a rumble test on my 124, with a blank 45, and the needle down, volume turned way up, no rumble, just random noise caused by the needle rubbing against the vinyl. Have you also cleaned and oiled the intermediate pully? Could the idler be rubbing on the step pully, because it's mal-adjusted? EVERYTHING must be checked and perfect, don't overlook anything.

We will keep trying, wish you could hear mine to compare!

Gene


All very good tips and found in the TD-124 restoration thread along with a lot of other things. I followed much the same path as Gene and have a table which currently seems about as quiet as possible.
 
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Hi
I think the Decca isn' t the issue because the V15 in an identical headshell makes exactly the same noise. So although it is rarely the case, the Decca isn't at fault this time! I have an SME weight somewhere that I can use to increase the mass. Will experiment. I am doubtful, but it would be great if additional headshell mass solved the problem. The SME shells are the light weight ones....

con

Given that the Shure exhibits the same issue I would expect that adding weight to the arm is not going to change the situation. I would look at the things Gene suggested in his post, and then swap arms.

I have mounted SME arms on wood cigar boxes for this sort of purpose as a temporary lash up - doing this will tell you whether or not the noise is transmitted through the platter or not. This avoids the need for an arm board, prevents the coupling you would have through the normally mounted arm board, and is very quick and easily done. You could also do this with the AT arm and a block of wood. (Or anything sufficiently stable to support the arm for a quick experiment.)
 
Hi
Thanks for all the advice! I will try adding a penny to the headshell with the Decca as a first experiment because it take only a minute. The pulleys are clean and shiny, but all I did was oil the idler bearing. I have not taken anything apart and cleaned it. Alignment appears good, but I am going to have to look at all the threads and internet info and check the whole drive train out. I will then try the arm experiments. I could pull the whole arm board with the sme off of the TD125 and probably just clamp it to the td124 for a simple experiment. You are right, if I still get the sound then it is coming through the platter. If not, then could be the AT arm. Gene, yes the noise vanishes as soon as you switch off the motor and let it coast on the lead in groove with stylus down. So the platter bearing assembly is not the problem. That motor has to be on and you only get the noise with the stylus down, so it isn't electrical. It is vibration. Will try the talcum powder trick as necessary. Might take me a day or two to get to all of this, but will report back.

Thanks for all the help guys!!

Don
 
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Hi
Thanks for all the advice! I will try adding a penny to the headshell with the Decca as a first experiment because it take only a minute. The pulleys are clean and shiny, but all I did was oil the idler bearing. I have not taken anything apart and cleaned it. Alignment appears good, but I am going to have to look at all the threads and internet info and check the whole drive train out. I will then try the arm experiments. I could pull the whole arm board with the sme off of the TD125 and probably just clamp it to the td124 for a simple experiment. You are right, if I still get the sound then it is coming through the platter. If not, then could be the AT arm. Gene, yes the noise vanishes as soon as you switch off the motor and let it coast on the lead in groove with stylus down. So the platter bearing assembly is not the problem. That motor has to be on and you only get the noise with the stylus down, so it isn't electrical. It is vibration. Will try the talcum powder trick as necessary. Might take me a day or two to get to all of this, but will report back.

Thanks for all the help guys!!

Don

Depending on serial number you will either have the later intermediate pulley with bearings in the chassis or the earlier one with the bearing in the pulley itself. To service the intermediate pulley remove the idler first taking careful note of the position and type of washers. The locking collar on the idler should not be in contact with the washers but perhaps 20 - 30 thousandths above it. Once removed loosen the screw that retains the little plate that keeps the intermediate pulley from falling off in transit and move to side. The pulley regardless of vintage can then easily be removed. Clean bearing(s) and spindle thoroughly with isopropyl alcohol or lacquer thinner (do not get on paint!) and then relubricate with 20 wt oil.

Let us know what specific intermediate pulley set up you have and we can advise on how best to lubricate the specific bearing(s).

I had assumed the motor had been cleaned and lubricated, but depending on vintage you can't get to the lower bearing to lubricate it without disassembling it first. I drill an oiling hole in the housing in such cases to allow for future lubrication. If such is the case you should rebuild the motor as soon as possible as dry, aged motor bearings will increase the load on the motor contributing substantially to the noise issue. They may also be quite sloppy which will also contribute significantly to the noise issues. In the mean time I would try to clean and lubricate both upper and lower motor bearing assemblies.
 
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HI
Thanks for all the info. I will pull it apart tonight or tomorrow and have a good look. I recall oiling the motor bearings as in a manual I downloaded, but I will check it all over again. I may rebuild the motor. I did talk with Steve at the analog depot and if I do the rebuild he may have the parts. Seems like a good thing to do. I can make the sound lessen by pressing on the turntable frame and compressing the old mushrooms a bit. It is a small change, but noticeable. I suspect that the motor is vibrating even though you really cannot feel it or hear it. Must be getting in through the belt or the suspension even though it is new. The gel grommets might help too. I will investigate the motor and pulleys and drivetrain as you all suggest and do the best I can to lube everything. Then we shall see if the noise lessens. Was listening again this morning and the table/arm/decca combo is simply astonishingly good. I will sort out the noise. If I can cut it by half that would be just fine.
Thanks again for all the advice, you guys are first rate. Being a tube amp rebuilder I hang out on the audio asylum vintage section mostly....good folks there as well.


cheers,
Don
 
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Given your previous comments I think the geltec bushings might help, and a total motor rebuild is in order. Steve's bearings are awesome, and I would wait for those to become available again..

Here's a link to motor rebuilding 101: http://homepage2.nifty.com/pantone/thorens/overhaul_1.htm

I only unsoldered a couple of wires and removed the voltage selector assembly along with the motor. I was able to move the top housing cover enough to have easy access to the bearing assemblies for their removal. Be careful to not strip the grub screws when removing the motor pulley, and be sure to tighten both fully on reinstallation. I have seen recommendations that the black screw be tightened first, but find no references in my service manuals.

There is a lot of good information on motor isolation and lubricants on this site as well. Here: http://homepage2.nifty.com/pantone/thorens/
 
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Don, Kevin has some very good advice. I might want to add that if you can, use 91% alcohol to soak the platter bearing, and use an ultrasonic cleaner if you have one. I ran my platter bearing through one, and although it took about 6 hours for the old oil to be removed, (I could see it floating free in the alcohol bath), the sintered platter bearings were as clean as I could hope to get them. I then let them dry by using the bathroom heater for 4 hours. After that, I used 20w "Turbine" oil" for lubrication by filling the housing to the top, (spindle removed) then applied heat with the bathroom heater to help the oil soak into the bearings. After talking to Schopper, (The expert on these tables), I added 3 drops of oil, 2 on the spindle shaft, one on the thrust bearing. Once every part of the transmission is running smoothly, you should get the 124 to run much quieter. Remember the idler also, oil, not grease, plastic washer on the bottom,, 1 or 2 fiber washers on the top, clearance as mentioned by Kevin or, if you can get a feeler gauge in there 1/64" as per the manual.
 
Dear Kevin,

The measurements are done with the SME 3009 , this arm has a extra decoupling in the tonearm base with the four rubbers can be very usefull with idler turntables for decoupling .
Inclosed a picture from one off mine TD124 with decoupled motor ,the motor is placed on rubber stuts on a separate base plate then 95 % off the vibrations are gone !
 

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Dear Kevin,

The measurements are done with the SME 3009 , this arm has a extra decoupling in the tonearm base with the four rubbers can be very usefull with idler turntables for decoupling .
Inclosed a picture from one off mine TD124 with decoupled motor ,the motor is placed on rubber stuts on a separate base plate then 95 % off the vibrations are gone !

I would think this would work quite well, and something to think about. Just have to make sure the motor can't move and the height is correct.

I recently removed the four little rubber bushings on the bedplate of one of my SME 3009 arms, and subjectively am pleased with the result. My TD-124 is now quiet enough that I noticed no difference with them in or out noise wise.. In terms of arm performance it resulted in noticeably better defined bass lines, less midbass bloat, and better imaging, etc. Worthwhile IMHO if the table is quiet enough..
 
TD124low humming

The low humming between tracks or silent passage can be eliminated by simply removing the mushrooms. But also please check that the main spindle bearing is well lubricated. I've had this problem for a long while, until I chanced upon someone who'd removed the mushrooms to kill the hum.
 
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